docs: def _remove_uri_scheme_from_textbuffer(self, scheme):
          """Remove the URI scheme of a new external link from the textbuffer."""
          length = len(scheme)
          while length:
              if length < len(self._textbuffer[-1]):
                  self._textbuffer[-1] = self._textbuffer[-1][:-length]
                  break
              length -= len(self._textbuffer[-1])
              self._textbuffer.pop()